1. Technical Field
The present invention relates to an image reading apparatus that reads images of documents.
2. Related Art
A certain type of scanner, which is an example of an image reading apparatus, includes an auto document feeder (ADF) for automatically feeding and reading a plurality documents (for example, see JP-A-2012-100115). The documents are transported toward a read section by the ADF. In such a scanner, in an area of the transport path where the transport path faces the read section, the transport path is narrowed to enable each transported medium (document) to come into close contact with the read section thereby the read section can read the documents with high accuracy. The transport path in JP-A-2012-100115 is defined by the image reading units 13 and 14 that are disposed vertically.
When a document is transported toward the read section, in the area that faces the read section in the transport path, the document may be pressed against the lower surface of the transport path to stabilize the orientation of the document in the area facing the read section. In such a case, in the narrow transport path in the area facing the read section, if a medium, which is the document, which has a high stiffness is transported, the medium may be caught on the transport path and its transport resistance may increase.
In JP-A-2012-100115, the space between the read surfaces of the image reading units 13 and 14, which are disposed vertically, is defined such that a thin medium M1 can pass therebetween and the read surfaces are urged by the elastic members 132 and 142 respectively such that the read surfaces approach each other (see FIG. 5 in JP-A-2012-100115). When a thick medium M2 is transported, the thick medium M2 passes between the read surfaces of the image reading units 13 and 14, so that the image reading units 13 and 14 are moved in directions the units 13 and 14 are separated from each other against the urging force of the elastic members 132 and 142. Such a structure produces a high transport resistance in transporting the thick medium M2.